The objectives of our research are to first, describe the molecular mechanisms involved in the renal transport of those drugs that are either organic cations or anions. Our approach to the problem is to study the transport of the organic ions in isolated luminal and antiluminal membrane vesicles which have been prepared from dog kidney cortex. Our second objective is to solubilize these two membranes and reconstitute transport by incorporating the solubilized protein into phospholipid vesicles. We will compare the kinetics from these phospholipid vesicles to those from the membrane vesicles. Our third objective is to isolate the transport proteins from both the luminal and antiluminal membranes. After solubilization of the membranes with anon-ionic detergent, the proteins can be isolated by classical chromatographic procedures. The means by which the transport proteins can be quantified throughout the isolation scheme is to reconstitute transport in phospholipid liposomes. Accomplishment of this objective will allow for the initiation of studies on the chemical properties of the transport. We hope to be able to combine the information obtained to describe the transcellular events in the renal transport of organic ions.